1. Field of the Invention
This invention relates to a temperature estimation apparatus for an aeroplane gas turbine engine.
2. Description of the Related Art
In an aeroplane gas turbine engine equipped with a high-pressure turbine to be rotated by high-pressure gas injected from a combustion chamber of the engine and with a low-pressure turbine located downstream of the high-pressure turbine to be rotated by low-pressure gas passed through the high-pressure turbine, temperature at an inlet of the low-pressure turbine is usually detected by a temperature sensor to prevent the engine from overheating.
However, installation of the temperature sensor at (or near) the inlet of the low-pressure turbine would disadvantageously restrict the freedom of design layout and in addition, the temperature sensor itself must have an excellent heat-resistance. It will accordingly be preferable to estimate the inlet temperature of the low-pressure turbine based on the other temperature so as to make the engine smaller and more compact.
To cope with it, it has been proposed to detect rotational speed and outlet temperature of the low-pressure turbine, to calculate a correction value from the detected rotational speed of the low-pressure turbine and to obtain an estimated inlet temperature of the high-pressure turbine by adding the correction value to the detected outlet temperature, as taught by, for example, Japanese Laid-Open Patent Application No. 2002-106364.